Generally, a liquefied gas storage tank on land has a substantially cylindrical flat bottom and is used to store liquefied gas for fuels, such as liquefied natural gas (LNG), liquefied petroleum gas, and the like, and other liquefied gases such as liquefied oxygen, liquefied nitrogen, and the like. One example of such a cylindrical liquefied gas storage tank is disclosed in Japanese Patent Laid-open Publication No. Sho 56-120900.
FIG. 1 shows one example of a conventional full-containment type liquefied gas storage tank on land. Referring to FIG. 1, the liquefied gas storage tank includes a cylindrical tank body 3 formed through concrete casting on a foundation 1 and having an approximately dome-shaped cover.
The tank body 3, which is made of concrete, is provided therein with a heat insulating bottom 4 and a heat insulating wall 5, and a vapor barrier 2 is interposed between the tank body 3 and the heat insulating bottom 4 and between the tank body 3 and the heat insulating wall 5. Inside the heat insulating bottom 4 and the heat insulating wall 5, a container 6 is located to contain a cryogenic liquefied gas in a sealed state.
Since the container 6 directly contacts the liquefied gas, it may be made of a low-temperature carbon material or the like, which is capable of enduring cryogenic conditions.
Such a conventional liquefied gas storage tank is generally constructed to have the cylindrical tank body 3 by performing foundation work and repeating a process of pouring concrete into a mould on the foundation 1 to produce one wall having a predetermined height and a process of re-pouring the concrete into the mould to produce another wall of a predetermined height on the one wall after the one wall is completely hardened to have predetermined strength. Accordingly, the conventional liquefied gas storage tank has a problem in that considerable time is consumed for construction thereof.